Supplying fuel to internal combustion engines



July 21, 1936. s. OLSEN- 2, 4

SUPPLYING FUEL T0 INTERNAL COMBUSTION ENGINES Filed Dec 9, 1932 ASheets-Sheei 1:

I .6? mu m v /0 M 6/ um a 0 vum 76 /f 1 9 v 7 J6, I I 0 4 4/ U mvgmo;

wwaw

42 ATTORNEY' July 21, 1936.

s. OLSEN 4 Sheets-Sheet 3 Filed Dec. 9, 1932 5 W 3 0 I \(W f w m F k a x n F II I! .L ...,l WW; 4. 5 v 40 6 g G Wu 1 W 4 w v w Z W s. OLSEN July 21, 1936 SUPPLYING FUEL T INTERNAL COMBUSTION ENGINES 4 Sheets-Sheet 4 Filed 19,60. 9, 1932 Pump Jf/"OKfe lh mm.

40 X Vacuum m cm. (/9.

v IINVENTOR 1' wATToRNEY UNITED STATES PATENT OFFICE SUPPLYING FUEL TO. INTERNAL COMBUSTION ENGINES Stig Olsen, Stockholm, Sweden, assignor to Hesselman Motor Corporation Ltd., London, England, a corporation of Great Britain Application December 9, 1932, Serial No. 646,507

In Germany December 12, 1931 j '21 Claims. (Cl. 123-139) The present invention relates to supplying fuel to internal combustion engines and has particular reference to supplying fuel to engines of the airless or solid injection type. More specifically, the

invention relates to supplying fuel to aninternal combustion engine automatically under the influence of variations in pressure within the induction pipe of the engine, so as to provide a controlled ratio of the quantities of fuel and air supplied to the engine. Still more particularly, the invention relates to fuel supplying apparatus for engines adapted to be used to propel automotive vehicles, aircraft and the like.

The general object of the invention is to pro- 15 vide improved fuel supplying apparatus of the character described which will fulfill satisfactorily and in an improved manner the numerous different requirements for apparatus of this kind. The nature of the invention and the manner 20 in which the above general object and other and more specific objects are attained may best be understood from a consideration of the ensuing specification descriptive of several forms of apparatus suitable for carrying the invention into eifect and from the accompanying drawings in which:

Fig. l is a side elevation of an internal combusti'on engine provided with apparatus embodying the invention; 7 30 Fig. 2 is a view, partly in section, and on enlarged scale of part of the apparatus shown in Fig. 1;

Fig. 3 is a'section taken on the line 3-3 of Fig. 2; 35 Fig. 4

Fig. 2;

Fig. 5 is a view similar to Fig. 2 showing a different form of apparatus;

Fig. 6 is a section taken on' the line 6--6 of 40 Fig. 5; I,

Fig. 7 is a section taken on the line 1-1 of Fig. 6;

Fig. 8 is a more or less diagrammatic view illustrating a device which may be used with the apparatus shown in Figs. 5 to 7;

Fig. 9 is a view similar to Fig. 1 showing part of an engine equipped with still another form of apparatus;

Fig. 10 is a section on enlarged scale taken on the line Ill--I0 of Fig. 9;

Fig. 11 is a section showing apparatus constructed in accordance with the invention applied to a different type of pump;

Fig. 12 is a section taken on the line I2-i2 of 5 Fig. 11; and,

is a section taken on the line 4-4 of.

Fig. 13 is a diagram illustrating the relation of the amount of fuel supplied to the induction pipe pressure when apparatus according to the invention is employed.

Referring now to the drawings, Fig. 1 shows 5 in side elevation a multi-cylinder internal combustion engine equipped with fuel supplying apparatus according to the present invention. The motor is indicated generally at In and has the usual induction pipe ll through which air for combustion is drawn from the inlet l2. Flow of air through pipe I I is controlled by the usual butterfly throttle valve I3 actuated by rod M which is preferably connected to the usual throttle or accelerator pedal (not shown) when the engine 15 is used in avehicle.

The fuel supplying means comprises, in the present embodiment, a pump unit having a cas ing l5 and containing a plurality of pumps, one for each cylinder of the engine, .the construction of which will be-more fully described later. Fuel is admitted to the pumps through a fuel inlet pipe l6 and, if desired, the fuel supplying system may be of the circulating type in which excess fuel is returned to the supply tank from the pump unit through an outletcondult ll. The pump casing is conveniently removably secured to a bracket l 8 on the side of the engine and the drive for the pumps is effected through the medium of shaft I9 driven from the usual timing gears, or chain, the housing of which is indicated at 20.

At one end the pump casing l5 has an extension 2l which may or may not be integral with the casing l5 and which provides a cylinder having an opening adapted to be connected to the induction pipe ll of the engine as by means of connection 22 which is preferably detachably secured to the extension 2| and-which is also preferably flexible.

Considering now more particularly Figs. 2 to 4, I have shown in these figures the apparatus illustrated in elevation in Fig. 1. -Within the pump casing l5 there is located a'plurality of separate plunger pumps, indicated generally at 23. Each pump comprises a plunger 24 reciprocably mounted in a suitable guide and actuated and from this chamber fuel is discharged through passage 3| and the spring loaded discharge valve 32 to conduit 33 leading to the injection nozzle of the cylinder which is supplied with fuel by the pump. Fuel is admitted to the pump chamber through the inlet passage 34 in which is located the usual spring loaded check valve 35. Passage 34 is in communication with a chamber 36 in the head of the pump which provides a common supply chamber for all of the pumps and to which chamber fuel is supplied through the conduit I6. In the form of pump shown, the chamber 30 is provided with a relief valve 31 adapted to be contacted by the innerend of the plunger 24 before the plunger reaches the inner end of its stroke. This valve is held against its seat against pressure in the chamber 30 by means of the spring 38 engaging the spring retainer 39.

The present invention is not limited in its appllcation to this specific form of pump, as will hereinafter more fully appear but is applicable to other specific pump designs as well.

Control of the amount of fuel delivered per stroke of the pump plunger 24 is efiected by varying the length of the suction stroke of the pump plunger. The means for varying the suction stroke comprises an adjustable stop 40 in the form of a sleeve mounted around shaft 4| which is tumably mounted in the end walls of the casing in suitable bearings one of which is shown at 42. Sleeve 40 has limited turning movement with respect to shaft 4| and is biased so as to tend to turn counter-clockwise as viewed in Fig. 4 with respect to the shaft by means of a spring 43 connecti g the sleeve to an arm 44 rigidly secured to t shaft. A stop adapted to abut against a pin 43, serves to limit the turning movement of the sleeve with respect to the shaft under the influence of spring 43.

The specific form of pump construction just described forms per se no part of the present invention and the novel features thereof form the claimed subject matter of the application of Torbjorn Viktor Dillstrom, Serial No. 690,303, filed September 21, 1933.

The extension 2| carried by the, pump casing provides a cylinder 41 connected with the induction pipe of the engine by way of opening 48 and pipe 22. Slidably mounted upon a guide 49 fixed within the extension axially of cylinder 41 is a piston 50 and between the end wall 5| of the extension and piston 5|! are springs 52 and 53, between which is interposed a spring retainer 54 against which one end of each of the springs abuts. As indicated in the drawings, spring 52 is a relatively weak spring as compared with spring 53.

Attached to piston 50 and sliding therewith on the guide 49 is a cam member 55 which, in the illustrated embodiment is inthe form of a truncated cone. One end of shaft 4| projects into the extension 2| and has fixed thereto the arm 56. Ann 56 has secured thereto a follower 51,

preferably am'ustable; and advantageously in the form of a set screw or the like, as indicated in Fig. 3. Follower 51 is adapted to contact the surface of the cam member 55 and is advantageously maintained in contact therewith by means of a spring 58.

A secondarm 59 is also fixed to shaft 4| and movement of this arm and: consequently shaft 4| in clockwise direction, as viewed in Fig. 3 is prevented by a stop 50 which is preferably adjustable. A movable pin 6| mounted in the expend upon the length of the preceding suction stroke and this in turn will depend upon the position of rotation of the sleeves 40 on shaft 4|, which sleeves for the moment may be considered as fixed to shaft 4|.

The amount of air supplied to the engine is controlled by actuation of the throttle valve l3. Asthe valve I3 is moved toward closed position to throttle the air supply, the pressure in the induction pipe H (which is a negative pressure or vacuum) decreases and the decreased pressure is transmitted to cylinder 41 through connection 22. Decrease in pressure-in-cylinder 4'| tends to mov e piston 50 to the right, as shown in Fig. 2, against the resistance of the springs in the cylinder, since the face of the piston opposite cylinder 41 is in free communication with the, atmosphere by way of one or more ports 63 in the extension 2|.

As piston 50 moves to the right, the cam member 55 slides with respect to the follower 51 and causes arm 56 and shaft 4| to be turned in counter-clockwise direction, as viewed in Fig. 3. This in turn causes the stops 40 to also turn in counter-clockwise direction to shorten the suction strokes of the pumps and consequently cause them to deliver less fuel per stroke. Thus, decrease in pressure in the induction pipe automatically efiects decrease in the amount of fuel supplied. Conversely, when the throttle valve is opened and the induction pipe pressure increases piston 50 is moved to the left in Fig. 2 under the influence of the springs in cylinder 41 and shaft 4| together with stops 40 move under the influence of spring 58 in'clockwise direction, as viewed in Fig. 3 to provide a longer pump stroke.

The stop 50 limits the movement of arm 59 and shaft 4| in clockwise direction, as viewed in Figs. 3 and 4, and servesto determine the. maximum stroke of the pump plungers. By adjusting this stop the maximum pump stroke may be altered. The pin 6| provides a control for arbitrarily rendering the pumps inoperative irrespective of the position of the cam member 55. As will be evident from Fig. 3, if pin 6| is pushed inwardly of the casing it will operate to turn arm 59 and shaft 4| in counter-clockwise direction and thereby reduce the pump stroke to zero or 60.

to a value too small to cause an operative charge of fuel to be delivered by the pump. This movement can take place in any position of the cam member 55 since it involves merely moving the follower 51 away fromthe cam surface against 65 the resistance ofspring 58.

It will be evident from the foregoing description that the fuel supplying apparatus provides a simple and compact unit which may be readily detached from the engine without disturbing any of the adjustments and which comprises comparatively few and rugged parts not likely to be thrown out' of adjustment by vibrations and shocks to which apparatus of this kind is necessarily subjected when applied to vehicle or air- 75 l plane engines. By mounting the piston 50 on a central guide the amount of friction between the sponse to comparatively slight changes in pressure within cylinder 41 and the substantially direct cor motion between the piston 50 and the stops 40 reduces the likelihood of time lag in the apparatus which mechanism of more complicated nature might produce due to friction and the like. Also it is to be noted the arrangement eliminates possibility of inaccurate adjustment of the pumps due to lost motion in the mechanism.

Initial adjustment of the piston 50 with respect to the position of the adjustable stops'lfl is readily effected by means of the adjustable follower 51.

The resilient connection provided by springs 43 between shaft 4| and the stop sleeves 40 forms per se no part'of the present invention but pro.- vides a desirable means for preventing adjustment of the stroke of the pump plungers to take place at an undesired point in the working cycle. These springs have insuflicient strength to move the plungers on their discharge strokes against the pressure in the pump chambers and if the pressure responsive piston 50 is moved to decrease the stroke of the pumps the several stop i sleeves 40 will not effect the desired adjustment until the pump plunger with which they are individually associated is positively lifted by its tappet 25. This resilient connection to the stop sleeves permits the pressure responsive piston to move immediately upon change in pressure in the cylinder, without having to force any of the pump plungers against pump discharge pressure thus making the device more sensitive and it also prevents adjusting movement of the pump plungers in a manner which might cause a slight injection of fuel from the pump at the wrong time in the engine cycle, as for example during the exhaust stroke of the piston in the engine cylinder.

In order to provide for the maximum of fuel economy while at the same time insuring reliability of combustion and consequent evenness of engine operation throughout the entire working range of the engine from idling load to full load, the amount of fuel and air supplied to the enat a controlled ratio, and this ratio may be most conveniently considered in terms of the amount of fuel supplied for-each working stroke of the engine and the pressure existing in the induction pipe as determined by the position of the throttle valve, which pressure is indicative of the quantity of air drawn into each engine cylinder per working stroke. This ratio should be different for different loads on the engine and shouldprovide a mixture relatively rich in fuel at idling and full loads as compared with the richness of the fuel mixture supplied at intermediate loads. The relatively rich mixture at idling load' is necessary in order to insure reliable and even idling of the engine, and at full load the mixture should be sufliciently rich in fuel to use up all of the air supplied to the engine in order that the maximum power may be derived from an engine of given dimensions. The obtaining of maximum power from the engine at full load and the obtaining of steady idling, by the use of a relatively rich mixture, is secured at the expense of maximum fuel economy, but the considerations of obtaining maximum power and steady idling outweigh the necessity for maximum fuel economy in most internal combustion engine applications. 5

At intermediate engine loads satisfactory engine operation is obtainable and improved fuel economy is also obtainable by the use of fuel mixtures having a higher ratio of air to fuel than the ratioor ratios most suitable for use at full load and idling load.

In accordance with the present invention, I provide for the supply to the engine of a fuel mixture having a ratio of fuel to air which varies with variations in engine load and is proportioned so as to provide a relatively rich mixture at idling load, which mixture decreases progressively in richness as the load increases from idling load to a load within the upper range of engine loads, and which then progressively increases in richness as the load further increases,'to a degree again providing a relatively rich mixture at full engine load, so that at this latter load all of the air supplied to the engine may be utilized and the maximum amount of plied to the engine consists in the provisionof diiferent resistances to movement of the pressur responsive piston 50, which resistances cause different amounts of movement of the piston in different load ranges of the engine in response to a given variation ,in the pressure within the induction pipe of the. engine. of the invention just described the different resistances are provided by the springs 52 and 53 of different strength. In the position of the apparatus as shown in Fig. 2, the pressure in the. cylinder 41 is substantially atmospheric (correspending to open throttle) and movement of the piston to the right as the throttle is moved from open position is first resisted by the comparatively weak spring 52 and this resistance continues to increase at a definite proportional rate ever, different from the rate of increase of regine for each working stroke must be supplied sistance provided by the weak spring 52. It will be evident'that' the same effect may be obtainedtby employing a plurality of relatively weak springs 55 in place. of the single stifi spring 53.

With the springs arranged in series as shown in Fig. 2, the strong spring 53 acts asan abutment for the spring retainer 54, and as spring 52 is compressed by-initial movement of piston 50 to the right from the position shown in the figure, spring 53 will yield by a certain amount as spring 52 is compressed due to the force transmitted to it by the latter spring. The relative strength of the two springs is however such that forall practical purposes spring 53 act@ as a fixed abutment until force from the piston is transmitted directly to it either by contact of the piston with the retainer or because of the fact that the resiliency of spring 52 is fully taken up. It may thus be said that the weaker spring essentially determines the resistance to move ment of the piston in the range of piston movement where this spring is active and that there- In the embodiment 35 of the variation in fuel-air ratio obtained by apparatus of the character just described. In this diagram, ordinates represent length of pump stroke and consequently quantity of fuel sup .plied and abscissa represent the degree. of vacuum in the induction pipe (measured in centimeters of mercury). From the diagram it will be evident that in the range of high engine loads a comparatively slight change in induction pipe pressure effects a relatively large change in the amount of fuel supplied. Expressed in another way, it may be said that in the range of high engine loads there is relatively little variation in the amount of air admitted as com red with the variation 11 the amount of fuel upplied. The part of the curve representing the fuel-air ratio in the range of high load is given the above described character due to the comparatively weak spring resistance, which permits relatively great movement of the pressure responsive piston under the influence of comparatively slight changes in induction pipe pressure.

In the lower load range a given variation in.

induction pipe pressure produces a relatively smaller variation in the amount of fuel supplied.

This is due to the increased resistance provided by the strong spring 53 or its equivalent. In other words, it may be said that for comparatively low engine loads a given variation in the amount of air supplied is accompanied by a smaller variation in the amount of fuel supplied than is the case in the range of high engine loads. If we again refer to the diagram of Fig. 13, it

- will-- be evident that apparatus productive of .curves of the character of curves 0 andb of this diagram will provide for variations of the character above described in the richness of the fuelair mixture. If we take curve a, for example, and substitute for this curve a curve that would be produced if a single spring-adapted to give the same fuel-air ratio at idling and full loads as curve awere substituted in the construction shown for the springs 52 and 53, the substituted curve would be in the form of a straight line connecting the'two ends of curve a. If, now, we compare curve a with this suppositious straight line curve, it will be evident that as the degree of vacuum decreases from that obtained at idling load, the increase in the amount of fuel corresponding to a given decrease in the amount of vacuum and consequent increase in the amount of air supplied to the engine when curve a is followed, is less than it would be if the straight line curve were followed, until the point a of curve a is reached. Consequently, during this range of operation, as the load increases from idling load,

creased due to the fact that complete combustion of all of the fuel is insured because of the presence of an ample supply of excess air. From the point a to the full load end of the curve a, the amount of fuel supplied for a given decrease in vacuum increases-much more than the increase in the amount of fuel for a corresponding given decrease in vacuum on the straight line curve. Consequently, in this range of operation, the fuel mixture increases in richn'ess as the load increases, thus enabling a fuel mixture to be'supplied at full load in" which there is enough fuel present to consume all of the air that can be drawn into the cylinder.

' the lever I5 is turned and will consequently lower v In this connection, it may be well to point out the known fact that in internal combustion en gines of the injection type the maximum power of a given engine is not determined by the amount of fuel that can be injected, since it is relatively 5 easy inject any desired quantity of fuel into pensated for and in Figs. 5 to '7, I have shown an arrangement which provides an additional con- 20 trol whereby the position of the stop sleeves may be varied with respect to the pressure responsive piston in any given position of the piston. In this arrangement the pump construction is the same as that previously described in connection 25 with Figs. 1 to 4 as is also the construction of the mechanism comprising the pressure responsive piston and cam member. In the present arrangement the shaft 4| has fixed thereto a. bell crank comprising an arm 64 and an arm 65. A 30 lever 66 is rotatably mounted at one end on a. pin 61 journaled in the casing extension 2| and having an eccentric part 68 around which one end of lever 66 is pivoted. Intermediate its ends lever 66 carries a roller 69 adapted to contact 35 the surface of the cam member 55. The free end of lever 66 is adapted to abut against an adjustable set screw 10 onarm 64. An adjustable stop for determining maximum pump stroke is p'rovided by the set screw H on arm 64, which is 40 adapted to abut against the bracket 12 beneath I the end of this arm. .The pin 6| for arbitrarily turning shaft 4| to shut off the fuel supply acts on the end of arm 65 and an adjustable set screw 13 is provided in the casing for limiting movement of shaft 4| under the influence of pin 6| by providing a stop adapted to engage the projecting outer end M of arm 64. Pin 61 has fixed thereto any suitable means, such as lever 15, for turning the eccentric part 68 to shift the position of-lever 66.

The operation of this form of apparatus is similar to that previously described with respect to the manner in which the pump stroke is varied by movement of piston 50. It will be evident, however, from Fig. 6 that with the cam member 55 in any given position, turning movement of lever 15 will raise or lower the left hand end of lever 66, depending upon the direction in which or raise the right hand end of lever 66. This in turn will cause arm 64 to be moved to shift the position of the stop sleeves governing the stroke of the pump plungers. If for example, lever 15 is turned clockwise,.as aviewed in Fig. 6, it will result in turning shaft 4t, in counterclockwise die rection, thus reducing the amount of fuel sup plied by the pumps.- This arrangement may advantageously, be used in connection with a viation engines where, due to changes in the density of the air at different altitudes, the differential pressure acting on piston 50 will be different for a given value of induction pipe pressure.

In Fig. 8, I have shown more or less diagrammaticallya suitable bellowsan'angement for conwith variations in atmospheric pressure.

a illustrate the manner in which this mechanism functions, let it be assumed that the apparatus shown in Figs. 5 to 8 is installed on an airplane engine. When the engine is on the ground a given value of pressure in theinduction pipe will produce, let us say, a. differential pressure of five pounds per square inch acting on the piston. This will move the piston a certain distance against the action of the springs and will provide a certain definite length of pump stroke. It, now, the craft in which the engine is mounted rises to a high altitude with the throttle control maintaining the same induction pipe pressure, the decrease in atmospheric pressure will cause a decrease in the. diflerential pressure acting on the piston to a value less than that assumed and the piston will move to the left. This will cause an increase in the amount of fuel supplied, although,

as assumed, the induction pipe pressure remains constant. This undesirable variation in the rate of fuel'supply with constant induction pipe pressure is avoided by apparatus such as is shown in Fig. 8, since upon decrease in atmospheric pressure the bellows I expands and turns lever I in clockwise direction, thus, as previously explained, moving lever 00 and arm 60 so as to reduce the fuel supply. Thus, the movement of arm i5, tending to cause a decrease in fuel supply compensates for the tendency of the fuel supply to be increased due to reduction in atmospheric pressure.

It will be evident that the control afforded by the lever I5 may be employed to compensate for other factors of operation occurring in connection with different engine uses. Thus, for example, in the case of a vehicle engine adapted to be operated at ground level, this control may be employed to provide a richer or leaner mixture in order to take care of special operating conditions such as cold weather starting and. the like.

In connection with this control, it is to be noted that it does not serve to alter the characteristic form of the curves illustrated in Fig. 13 but serves to raise or lower any given curve substantially parallel to itself in the diagram If it is desired to alter the characteristics of the curves, this is done by altering the strength of the springs resisting the movement of piston 50 and it will be evident that the strength of these springs can readily be altered by making adjustable the abutmentsagainst which they act or by the substitution of springs of different strengths. It is further to be noted that more than two springs of different strengthscan be arranged in series between the cylinder casing and the pump piston in order to provide resistance varying at more than two difierent rates.

In the forms of apparatus described, the cam member is in the form of a truncated cone, but it will be apparent that other cam formsmay be employed and it will further be evident that the same effect obtained by the eccentric part 68 may readily be obtained by employing an eccentrically mounted cam member which can be turned to present different axial contours for engagement with the cam follower or' by adjusting by hand or automatically the distance of the follower from the cam, for example, by means of the set screw 51 shown in Fig. 3. s I

Turning now to Figs. 9 and 10, I have shown a different form of construction in which the extension 2| provides a cylinder 41 the axis of which is transverse to the axis of the pump shaft I. In this arrangement the piston 50 is fixed to the guide stem 49a which is slidably mounted in the casing extension 2i. Lever I8 is fixed to the end of shaft 4i and at its upper end is forked to embrace the guide 49.. Spring 19 and pin 80 act to hold lever I8 in engagement with a collar 8| slidably moim'ted on guide 09 and adjustably fixed axially of the guide by means of the set screw 02 abutting against pin 83 passing through a collar 0! and a. slot 80 in the guide stem 49a. The adjusting screw 82 serves to fix the initial position of adjustment of the lever 18 and shaft BI with respect to piston 50. The set screw 85 serves to limit the maximum pump stroke and the supply of fuel may be arbitrarily shut off by actuation of pin 5i. adapted to contact the lever pump casing I5 carries a plurality of plunger pumps, one of which is shown at 23. Pump 23 comprises plunger 20a actuated on its discharge stroke by cam 27 acting through tappet 25 and actuated on its suction stroke by spring 29. Plunger 20a'is reciprocably in a turnably mount ed sleeve 9'! which is slotted at its lower end at 9% and vthe plunger is provided with a transverse arm or pin 89 engaging slot 88 so that the plunger is prevented from moving rotationally with respect to sleeve 81 but is free to reciprocate with respect thereto. Mounted on sleeve 81 so as to rotate therewith is a pinion 90 engaging a rack M on shaft 06 so that upon reciprocation of shaft 06 the plunger 20a is rotated about its axis.

In the embodiment of pump shown in Fig. 11 the pump chamber 30 is in communication with the fuel inlet passage 30a by way of ports 99 in the pump sleeve pump plunger 20a is provided with an annular recess ml which is in communication with the pump chamber 30 by wayof the vertical slot I02 in the plunger. Slot I02 is out of registry with the ports 99 and the upper edge of the recess IN is formed by a spiral edge indicated at I03. When the pump plunger is at the lower end of the stroke, the upper edge of the plunger is below I00, and the upper portion of the the level of ports 99 and the chamber 30 is filled with fuel. Injection commences when the upper edge of the plunger closes ports 99 and during the effective discharge stroke the recess IN is filled with fuel under pressure because of'the communication between this recess and the pump chamber through slot I02. Injection ceases when one of the inlet ports 99 is uncovered by: the spiral edge I0 3, such uncovering placing-the inlet pass sage 34d ber 30 by way of slot I02 and recess-m It will be evident that by varying the position of rotation of the pump plunger the edge I03 will uncover the inlet port in different positions of stroke of the plunger, thereby varying the eifect-ive charge stroke of the pump.

in communication withthejpump charninvention is concerned, other forms of pump con- 7-5.

10 move the shaft to the right, as viewed in Fig. 11;-

Movement of the shaft in this direction tends to increase the fuel supply.

In the cylinder 41 the pressure responsive piston 50 is carried by the guide 49. Between piston 15 50 and the end wall of the extension are the loading springs 52 and 53. Opening 48 provides a connection to the induction pipe of the engine and ports 63 permit atmospheric pressure to reach the outer face of piston 5|]. The slidably mounted guide stem 4% is provided with a cone tral axially slidable pin 95 abutting at one end against the abutment collar 92 and at its other end abutting against the adjusting screw 96. Pin 95 and set screw 96 provide "for initial adjustment of the relative positions of piston 58 and shaft 86.

A protecting boot 9! is advantageously placed restricted air supply, the fuel supplying device around the end of shaft 86 and spring 94.

The operation of this embodiment is in general similar to that previously described but due to the fact that both the piston 50 and the shaft as move reciprocably, the movement of piston 50 may be transmitted directly to the shaft by placing the axis of the piston in alignment with the axis of the shaft.

Shaft as extends through the casing and in order to arbitrarily shut off the fuel supply independently of the position of piston 50, a suitable Bowden wire control, such as is indicated in connection with the pins Si in the previously described embodiments, may be attached to the end of shaft 86 opposite the end shown in Fig. 11, so, that the shaft may be drawn to the left away from the pin 95. 4

For purposes of the present inventionrthe pinion 90 and sleeve 81 may be considered as an ad- J'ustable stop for varying the effective stroke of the pump plunger since these parts in effect provide a stop determining the position of rotation of the pump plunger which in turn determines the effective discharge stroke of the pump.

While in the present embodiment I have shown no structure corresponding to'the springs 43 providing a resilient connection between the shaft 4| and the stop sleeves 40 in the embodiments previously described, itwill be apparent that equivalent resilient means may readily be employed in the present embodiment between the shaft 86 and the stops determining the position of rotation of the pump plungers.

The movement of the guide stem 49b in the right hand direction and thereby the maximum delivery stroke of the pump pistons may be adiusted by means of a distance disc 88 or the like.

. From the foregoing description it will be .evident that apparatus constructed in accordance with the invention may be employed to give various different curves of'ratio of fuel and air supplied but I have found arrangements of the type shown to be very satisfactory in operation, these 7 "arrangements producingcurves of ratio of the.

character indicated in Fig. 13. In this figure it will be noted that the curves a and b-which represent ratios of different richness of the fuel mixture, both have the same general characteristics with respect to the variation of the amount of fuel in relation to the degree of vacuum. These and the induction pipe pressure but the relationship is difierent in two different ranges of load on 5 the engine. I have found from experience that most satisfactory results are obtained with airless injection engines if the change in the relationship between the amount of fuel supplied and the value of the induction pipe pressure occurs at apl0 proximately half engine load. In the curves shown in Fig. 13 the point of cha-ngein the relationship is indicated at a and b, respectively, and these points on the curves occur at the time when the resistance to movement of piston 50 15 in the apparatus is transferred from the weak spring 52 to the strong spring 53. 4

It is to be noted that in the several embodiments of apparatus shown, the adjustment is for maximum supply of fuel when atmospheric pres- 20 sure exists in the cylinder which communicates with the induction pipe. Thus, when the motor is at rest and induction pipe pressure is equal to that of the atmosphere, the device is adjusted for maximum fuel delivery. If, however, the engine 25 is started with the throttle valve adjusted for a ways adjustable as pointed out in the foregoing by suitable means such as set screws so that a movement of the vacuum controlled piston produces a quite definite delivery stroke of the fuel With regard to Fig. 13 and the curves shown 45 thereby it will'be seen that any other character can be given to these curves when for each acting range of the spring or springs the stiffness is predetermined in accordance with the actual operating conditions. Thus it will always be possible to 50 obtain a desired ratio of air to fuel.

While I have shown, for purposes of illustration and explanation, forms of apparatus which I consider to be most suitable for carrying the invention into effect, it will be apparent to those skilled 55 in the art that many changes and variations may be made in the specific design of the apparatus without departing from the scope of the invention and that for numerous of the specific elements herein illustrated, other equivalent elements may be substituted.

What I claim is: a

1. In fuel supplying means for internal combustionengines having an inductionpipe, the com; hination with a fuel pump, means for varying the efiective stroke of the pump, pressure responsive means adapted to move under the influence of variations in pressure in said induction pipe, and means for transmitting movement from said pressure responsive means to the first mentioned m means, of means providing a plurality of resistances for opposing movement of the pressure responsive means in response to decreasein said pressure, the last mentioned means comprising a, plurality of springs of different'strength arranged 9,048,406 so that movement of the pressure responsive member due to decrease insaid pressure is resisted first by a relatively weak spring and then by a relatively strong spring.

2. Fuel supplying means for internal combustion engines having an induction pipe comprising, in combination, a pump casing, a plurality of plunger pumps having plungers mounted in line within said casing, a shaft movably mounted in said casing to one side of the line of plungers, means associated with said shaft for causing movement of the shaft to vary the effective delivery strokes of said plungers, pressure responsive means adapted to move under the influence of variations in pressure in said induction pipe,

means for transmitting movement from said pressure responsive. means to said shaft, and a plurality of springsfor opposing movement ofithe pressure responsive means in response to decrease strength and acting {to oppose said movement first by a relatively weak spring and then by a relatively stronger spring.

prising, in combination, a fuel pump, means for varying the effective discharge stroke of the pump comprising a turnably mounted shaft, means providing a cylinder having an opening adapted to be connected to the induction pipe of an engine, a piston reciprocably mounted in said cylinder, spring means for resisting movement of said piston in response to decrease in pressure in said cylinder, a cam member operatively connected to and reciprocable with said piston, said cam member having a surface inclined with respect to' the axis of reciprocation of the cam and means comprising an arm in engagement-with the surface of said cam member for, causing turning movement of said shaft upon movement of said cam mem-- viding a cylinder having an opening adaptedto be connected to the induction pipe of an engine, a piston reciprocably mounted in said cylinder, spring means for resisting movement of said piston in response to decrease in pressure in said cylinder, a cam member connected to and reciprocable with said piston and mechanism comprising a part in engagement withthe surface ment of said shaft upon movement of said cam member, said spring means and said cam being constructed and arranged tocause less decrease in the efiective discharge stroke of the pump for a given :decrease in pressure in said pipe in the low same decreasein pressure in said pipe in the high load range of operation of the engine and said mechanism including a part movable to alter the position of said shaft relative to said cam mem- 70 .ber in a given position of the cam member;

, prising, in combination, a fuel pump, means for varying the effective discharge stroke of the pump, means providing a cylinder having an opening adapted to be connected to the induction 3. Apparatus of the character described com- I comprising a turnably mounted shaft, means proload range 'of operation of the engine than for the.

in said pressure, said springs being of different comprisinga turnably mounted shaft, means propipe of an engine, a piston reciprocably mounted in. said cylinder, spring means comprising portions of diiferent strength for resisting movement of said piston with different rates of resistance in different ranges of position of the piston in response to decrease in pressure in said cylinder, mechanism providing an operative connection for transmitting movement from said piston to said first mentioned means and means for arbitrarily moving said first mentioned mechanism independently 10 of said piston to render said pump inoperative.

'6. Apparatus of the character described comprising, incombinati'on, a fuel pump, means for varying the eflective discharge stroke of the pump 15 viding a cylinder-having an opening adapted to be connected to the induction pipe of an engine, arpiston reciprocably mounted in said cylinder, spring means for resisting movement of said piston in response to decrease of pressure in said cylinder, a cam member operatively connected to and reciprocable with-said piston, mechanism having a follower engaging the surface of said cam member and comprising an arm secured to said shaft for causing turning movement of the shaft upon movement of the cam member, said spring means and the surface of said cam member being constructed and arranged to cause less movement of said-arm for a given decrease in pressure in said pipe in the low load range of operation. of the engine than for the same decrease in pressure in said pipe in the high load range of operation of the engine and means for arbitrarily moving said follower out of contact with the cam surface and turning said shaft to a position rendering said duction pipe, a'piston reciprocably mounted in of said cam member for causing turning movepump ineflective independent of the position of said cam member. v

7. Fuel supplying apparatus for a multi-cyiinder internal combustion engine having an induction pipe comprising a plurality'of plunger pumps, one'for each cylinder of the engine, a movably mounted member having a plurality of stops associated therewith for varying the effective stroke of the pumps, means providing a cylinder having an opening adapted to be connected to said insaidpylinder, spring means for resisting movement of said piston in response to decrease .of pressure in said cylinder, said spring means comprising portions of diiferent strength arranged with the portion of greater strength resisting movement of said piston in the range of movement thereof corresponding to low air pressure in said cylinder and mechanism including'a part operatively connected to and reciprocable with said piston for moving said movably mounted member to vary the position of said stops;

--:--8. Fuel supplyingmpparatus for a-=multi-cylinder' internal combustion engine having an induction pipe comprising a casing, a plurality of plunger pumps, one for each cylinder of the engine, mounted in said casing, a turnably mounted shaft having aplurality of stops associated therewith for varying the stroke of saidpumps upon turning movement of the shaft, means pro- 65.

viding a cylinder at one end of the casing, said 5. Apparatus of the character described comcylinder having an opening adapted to be connected to said induction pipe and the axis of the cylinder being parallel to said shaft, a guide mounted axially of said cylinder, a piston slidably mounted on said guide and reciprocable in said cylinder, spring means for resisting movement of said piston upondecrease in pressure in the cylinder, a cam member connected to said piston and slidable on said guide, an arm fixed to said shaft, a lever ha\1ing a part adapted to engage said cam member and a part adapted to engage said arm for transmitting motion from said cam member to said shaft, and an adjustable pivot for saidlever for altering the position of rotation of said arm with the cam member in a' given position.

9. Fuel supplying apparatus for a multi-cylinder internal combustion engine having an induction pipe comprising a casing, a purality of plunger pumps, one for each cylinder of the engine, mounted in said casing, a reciprocably mounted shaft having a plurality of stops associated therewith for varying the effective stroke of' said pumps upon movement of the shaft, means providing a cylinder at one end of the casing, said cylinder having an opening adapted to be connected to said induction pipe and the axis of the cylinder being in alignment with said shaft, a piston reciprocable in said cylinder, spring means for resisting movement of said'piston upon decrease in pressure in the cylinder, and means for transmitting movement of said piston directly to said shaft, said spring means comprising portions of different strength and the portion of greater strength being arranged to resist movement of said piston in the range of movement thereof corresponding to low air pressure in said cylinder.

. 10. Fuel supplying apparatus for a multi-cylinder internalcombustion engine having an induction pipe comprising a casing, a plurality of plunger pumps, one for each cylinder of the engine, mounted in said casing, a reciprocably mounted shafthaving a plurality of racks thereon, rotatably mounted stops engaging said racks for varying the effective stroke of said pumps 'upon movement of the shaft, means providing a cylinder at one end of the casing, said cylinder having an opening adapted to be connected to said induction pipe and the axis of the cylinder being in alignment with said shaft, a piston reciprocable in said cylinder, spring means'for resisting movement of said piston upon decrease in pressure in the cylinder and means for transmitting movement of said piston directly to said shaft, said spring means comprising portions of different strength and the portion of greater strength being arranged to resist movement of said piston in the range of movement thereof corresponding to low air pressure in said cylinder.

11. In charge forming apparatus for injection engines having a throttle controlled air admission conduit, the combination with fuel injecting means forseparately injecting fuel to the engine and pressure responsive means responsive to variations in the pressure of the controlled air in said conduit of mechanism including a device for delivering measured quantities of fuel to said fuel injecting means, said mechanism being adjustable in response to movement of said pressure responsive means and including parts arranged to move in response to a movement of the pressure responsive means corresponding to an'inc'rease in pressure in said conduit of given value when the load on the engine is in the range between idling load and an intermediate load at least as great as half load so as to increase the amount of fuel injected by an amount proportionately less than the increase in the amount of air supplied, whereby to decrease the proportion of fiiel in the fuelair mixture as the load on the engine increases in said range, and to move in response to a movement of the pressure responsive means corresponding to the same given value of pressure increase in said conduit when the load on the en ine is in the range between said intermediate load and full load so as to increase the amount of fuel injected by an amount proportionately greater than the increase in the amount of air supplied,

whereby to increase the proportion of fuel in the fuel-air mixture supplied to the engine as the load increases in the second mentioned range.

12. In. charge forming apparatus for injection engines to which air and fuel are separately supplied and in which air is admitted to the engine through a throttle controlled air admission conduit, a fuel pump means for varying the proportion of fuel to air supplied to the engine comprising pressure responsive means movable un-- der the influence of variations in pressure in said admission conduit, means for causing the movement of said pressure responsive means corresponding to a given pressure change in said con- 'duit in the range of engine loads from idling load to an intermediate engine load to vary the effective discharge stroke of the pump by a relatively small amount, whereby to cause a fuel-air mixture having a progressively smaller proportion of fuel to be supplied to the engine as the load increases within said range, and means for causing the movement of said pressure responsive mechanism corresponding to the same given pressure change in said conduit in the range of engine loads from said intermediate load to full load to vary the effective discharge stroke of the pump by a relatively large amount, whereby to cause a fuel-air mixture having a progressively larger proportion of fuel to be supplied to the engine as the load increases in the second mentioned range.

13. In charge forming apparatus for injection engines to which air and fuel are separately supplied and in which air is admitted to the engine through a throttle controlled air admission conduit, a fuel pump means for varying the proportion of fuel to air supplied to the engine comprising pressure responsive means movable in response to variations in pressure in said conduit, means for causing the movement of said pressure responsive means corresponding to a given pressure change in said conduit in the range of engine loads from idling load 'to an intermediate load at least as great as half load to vary the effective discharge stroke of the pump by a relatively small amount, whereby to cause a fuel-air mixture having a progressively smaller proportion of fuel to be supplied to the engine as the load increases within said range, and means for causing the movement of said pressure responsive means corresponding to the same given pressure change in said conduit in the load range of engine loads from said intermediate load to full load to vary the effective discharge stroke of the pump by a relatively large amount, whereby to cause a fuel-air mixture having a progressively larger proportion of fuel to be supplied to the engine as the load increases in the second mentioned range. I

stroke of the pump by an amount sufficiently from idling load, and means operative only in the high load range of the engine for causing the amount of variation in the effective discharge. stroke of the pump corresponding to said given pressure change tobe increased sufficiently to provide a fuel-air mixture having-a larger proportion of fuel as the load increases in said high load range.

15. In the operation of an internal combustion engine of the injection type to which air is admitted through an induction pipe and in which the amount of fuel injected is controlled by the pressure in said induction pipe, that improvement which consists in causing a pressure change of given value in said pipe when the engine is opcrating in the range of loads between idling load and an intermediate load to change the amount of fuel injected by an amount such that the proportion of fuel in the fuel-air mixture admitted to the engine decreases as the load increases in said range and causing the same given value of pressure change in said pipe when the engine is operating in the range of loads from said intermediate load to full load to change the amount of fuel injected by an amount such that the proportion of fuel to air in the fuel-air mixture supplied to the engine increases as the load increases in the second mentioned range.

16. In the operation of an internal combustion engine of the injection type to which air is admitted through an induction pipe and in which the amount of fuel injected is controlled by the pressure in said induction pipe, that improvement which consists in causing a pressure change of given value in said pipe when the engine is operating in the range of loads from idling load to an intermediate load at ,least as great as half load to change the amount of fuel injected by an amount such that the proportion of fuel in the fuel-air mixture admitted to the engine decreases as the load increases in said-range and causing the same given value of pressure change in said pipe when the engine is operating in the range of loads from said intermediate load to full load to change the amount of fuel injected by an amount such that the proportion of fuel to air in the fuel-air mixture supplied to the engine increases as the load increases in the second mentioned range.

17. In the operation of an internal combustion engine of the injection type to which air is admitted through a throttle controlled induction pipe through which a throttled supply of air is admitted at partial load on the engine and in which the amount of fuel injected is controlled by the pressure in said pipe, that improvement which consists in causing the amount of fuel injected to be increased in response to an increase in pressure of given value in said pipe by an amount proportionally less than the increase in the amount of air supplied due to said increase in pressure when the amount of throttling is. re-

duced to compensate for increase in engine load whereby to effect a reduction in the proportion of fuel in the fuel-air mixture supplied to the engine as the load increases in said range, and causing the amount of fuel injected to be in creased in response to an increase in pressure in said pipe of the same given value by an amount proportionally greater than the increase in the amount'of air supplied due to said increase in pressure when the amount of air throttling is "further reduced to compensate for increase in engine load in the range of loads from such intermediate loadto full load, whereby to effect an a increase in the proportion of fuel in the fuel-air mixture supplied to the engine as the load increases in the second mentioned range.

18. In charge forming apparatus for injection engines to which fuel and air are separately supplied, the combination with a throttle controlled air admission conduit, a fuel pump, means for varying the effective discharge stroke of the pun-1p, pressure responsive means movable under the influence of the variations in pressure of the controlled air in said admission conduit, and means for transmitting movement from said pressure responsive means to the means for varying the effective stroke of the pump, of means providing resistance opposing the movement of the pressure responsive means occasioned by decrease in said pressure, the means providing such resistance being yieldable and comprising portions of different strength arranged to provide proportionately less resistance per unit decrease in said pressure in the range of pressures from normal maximum pressure to an intermediate pressure than in' the range of pressures below said intermediate pressure.

19. In charge forming. apparatus for injection engines to which fuel and air are separately pump pressure responsive means movable under the influence of the variations in pressure of the controlled air in said admission conduit, and means for transmitting movement from said pressure responsive means to the means for varying the effective stroke of the pump, of spring means providing resistance opposing movement of the pressure responsive means occasioned by decrease in said pressure, said spring means comprising portions having different strengths arranged for a portion of lesser strength to essentially determine the resistance opposing movement of the pressure responsive means occasioned by decrease in said pressure from the normal maximum value to an intermediate value and for a portion of greater'strength to essentially determine the resistance to movement of the pressure responsive means occasioned by decrease in said pressure to a value less than said intermediate value.

20. In charge forming apparatus for injection engines to which fuel and air are separately sup-v plied, the combination with a throttle controlled air admission conduit, a fuel pump, means for varying the effective discharge stroke of the pump, pressure responsive means movable under the influence of the variations in pressure of the controlled air in said admission conduit, and means for transmitting movement f om said pressure ing the effective stroke of the pump, of spring means providing resistance opposing the movement of the pressure responsive means occasioned by decrease in said pressure, said spring means comprising portions having different strengths including one portion having a strength several times as great as other portions, said portions being arranged for a portion of lesser strength to essentially determine the resistance opposing movement of the pressure responsive means occasioned by decrease in said pressure from the normal maximum value to an, interresponsive means to the means for varymediate value and for said one portion to essentiallydetermine-the resistance to movement of ment of said pressure responsive member into turning movement of said part whereby to efiect control of the effective stroke of the pump, and

spring means providing resistance opposing the movement of the pressure responsive means occasioned by decrease in said pressure, said spring means comprising portions having different strengths arranged for a portion of lesser strength to essentially determine the resistance opposing movement of the pressure responsive means occasioned by decrease in said pressure from the normal maximum value to an intermediate value and for a portion of greater strength to essentially determine the resistance to movement of the pressure responsive means occasioned by decrease in said pressure to a value less than said intermediate value.

STIG OLSEN. 

